Buggy code:
public class Java extends Task { private CommandlineJava cmdl = new CommandlineJava ( ) ; private Environment env = new Environment ( ) ; private boolean fork = false ; private boolean newEnvironment = false ; private File dir = null ; private boolean failOnError = false ; private Long timeout = null ; private String inputString ; private File input ; private File output ; private File error ; protected Redirector redirector = new Redirector ( this ) ; protected RedirectorElement redirectorElement ; private String resultProperty ; private Permissions perm = null ; private boolean spawn = false ; private boolean incompatibleWithSpawn = false ; private static final String TIMEOUT_MESSAGE = "Timeout:<seq2seq4repair_space>killed<seq2seq4repair_space>the<seq2seq4repair_space>sub-process" ; public Java ( ) { } public Java ( Task owner ) { } public void execute ( ) throws BuildException { } public int executeJava ( ) throws BuildException { } protected void checkConfiguration ( ) throws BuildException { } protected int executeJava ( CommandlineJava commandLine ) { } public void setSpawn ( boolean spawn ) { } public void setClasspath ( Path s ) { } public Path createClasspath ( ) { } public Path createBootclasspath ( ) { } public Permissions createPermissions ( ) { } public void setClasspathRef ( Reference r ) { } public void setJar ( File jarfile ) throws BuildException { } public void setClassname ( String s ) throws BuildException { } public void setArgs ( String s ) { } public void setCloneVm ( boolean cloneVm ) { } public Argument createArg ( ) { } public void setResultProperty ( String resultProperty ) { } protected void maybeSetResultPropertyValue ( int result ) { } public void setFork ( boolean s ) { } public void setJvmargs ( String s ) { } public Argument createJvmarg ( ) { } public void setJvm ( String s ) { } public void addSysproperty ( Environment . Variable sysp ) { } public void addSyspropertyset ( PropertySet sysp ) { } public void setFailonerror ( boolean fail ) { } public void setDir ( File d ) { } public void setOutput ( File out ) { } public void setInput ( File input ) { } public void setInputString ( String inputString ) { } public void setLogError ( boolean logError ) { } public void setError ( File error ) { } public void setOutputproperty ( String outputProp ) { } public void setErrorProperty ( String errorProperty ) { } public void setMaxmemory ( String max ) { } public void setJVMVersion ( String value ) { } public void addEnv ( Environment . Variable var ) { } public void setNewenvironment ( boolean newenv ) { } public void setAppend ( boolean append ) { } public void setTimeout ( Long value ) { } public void addAssertions ( Assertions asserts ) { } public void addConfiguredRedirector ( RedirectorElement redirectorElement ) { } protected void handleOutput ( String output ) { } public int handleInput ( byte [ ] buffer , int offset , int length ) throws IOException { } protected void handleFlush ( String output ) { } protected void handleErrorOutput ( String output ) { } protected void handleErrorFlush ( String output ) { if ( ( redirector . getErrorStream ( ) ) != null ) { redirector . handleErrorFlush ( output ) ; } else { <START_BUG> super . handleErrorOutput ( output ) ; <END_BUG> } } protected void setupRedirector ( ) { } private void run ( CommandlineJava command ) throws BuildException { } private int fork ( String [ ] command ) throws BuildException { } private void spawn ( String [ ] command ) throws BuildException { } private void setupExecutable ( Execute exe , String [ ] command ) { } private void setupEnvironment ( Execute exe ) { } private void setupWorkingDir ( Execute exe ) { } private void setupCommandLine ( Execute exe , String [ ] command ) { } private void setupCommandLineForVMS ( Execute exe , String [ ] command ) { } protected void run ( String classname , Vector args ) throws BuildException { } public void clearArgs ( ) { } protected ExecuteWatchdog createWatchdog ( ) throws BuildException { } private void log ( Throwable t ) { } public CommandlineJava getCommandLine ( ) { } public SysProperties getSysProperties ( ) { } }

Fix:
super . handleErrorFlush ( output ) ;